### Abstract

Quantum-inspired models have recently attracted increasing attention in Information Retrieval. An intriguing characteristic of the mathematical framework of quantum theory is the presence of complex numbers. However, it is unclear what such numbers could or would actually represent or mean in Information Retrieval. The goal of this paper is to discuss the role of complex numbers within the context of Information Retrieval. First, we introduce how complex numbers are used in quantum probability theory. Then, we examine van Rijsbergen's proposal of evoking complex valued representations of informations objects. We empirically show that such a representation is unlikely to be effective in practice (confuting its usefulness in Information Retrieval). We then explore alternative proposals which may be more successful at realising the power of complex numbers.

Original language | English |
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Title of host publication | ICTIR'11 Proceedings of the Third international conference on Advances in information retrieval theory |

Place of Publication | Berlin, Heidelberg |

Publisher | Springer-Verlag |

Pages | 346-350 |

Number of pages | 5 |

ISBN (Print) | 978-3-642-23317-3 |

Publication status | Published - 12 Sep 2011 |

Externally published | Yes |

### Publication series

Name | Lecture Notes in Computer Science |
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Publisher | Springer-Verlag |

Volume | 6931 |

### Keywords

- information retrieval
- search strategies
- quantum probability theory

## Cite this

Zuccon, G., Piwowarski, B., & Azzopardi, L. (2011). On the use of complex numbers in quantum models for information retrieval. In

*ICTIR'11 Proceedings of the Third international conference on Advances in information retrieval theory*(pp. 346-350). (Lecture Notes in Computer Science; Vol. 6931). Springer-Verlag.